Prior-art devices for guiding a power tool along an advancing direction consist of a baseplate that can be fastened to a substrate by a fastening means, and of a guide rail that can be joined to the baseplate and that has a contoured means. The power tool is arranged on the guiding device by means of a guide carriage and can be moved along the guide rail by means of an advancing mechanism. The guide carriage has a counter-contoured means that can be made to engage with the contoured means.
When core holes are drilled, large forces and torques are exerted that have to be absorbed by the guiding device. For this reason, the guiding device has to stand securely and has to be fastened to a substrate. When core holes are being drilled in steps, the problem arises that the footprint on which the baseplate of the guiding device can be fastened is very limited in size.